Allow the lander to reach a speed of -10 m/s, turn on the thruster (with the space bar) until it reaches a speed of +10 m/s, turn off the thruster (with the space bar), and wait until it crashes.
Watch the velocity readout, and be prepared to summarize the patterns you observe!
Velocity and Acceleration
Lessons learned from the Lunar Lander Sim.Measuring Acceleration
Filing Cabinet Sim